<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .one {
        background-color: red;
      }
    </style>
  </head>
  <body>
    <div id="box" class="one" style="width: 100px; height: 100px"></div>
    <script>
      // 注意: 通过style只能获取到行内样式
      console.log(box.style.backgroundColor)
      console.log(box.style.width)
      console.log(box.style.height)
    </script>
  </body>
</html>
